DESCRIPTION (Applicant's Abstract): Among women of childbearing age, depression is among the most common chronic illnesses and antidepressant drugs are among the most common long-teem medications. For women with depressive illness, available data give unclear guidance about continuing antidepressant drug use during pregnancy. We propose a population- based study of birth outcomes among a cohort of children exposed to antidepressant drugs in utero and a comparison co hon of unexposed children. We will use computerized pharmacy data to assess antidepressant exposure. Potential adverse effects (e.g. congenital malformations, developmental delay) will be identified using newborn examination records, outpatient pediatric records, and computerized visit data. Potential confounding factors (e.g. other prenatal exposures) will be assessed from maternal records Exposed and unexposed cohorts will be matched for maternal age and maternal history of depression treatment. Outcomes of exposed and unexposed children will be examined to test whether prenatal antidepressant exposure is associated with an increased likelihood of: Delivery prior to 37 weeks; Intra-uterine growth retardation; Poor neonatal adaptation; Specific congenital malformations; Clinically significant delay in motor language or social development These data should help to clarify the risks associated with continued use of antidepressant drugs during pregnancy and conception. Important strengths of the proposal include selection of a population-based sample of exposed children and use of a comparison group matched for maternal history of depression treatment.